Muffle furnace for heat treatment of steel



l,5]l7,l72 v A. E. RUDD MUFFLE FURNACE FOR HEAT TREATMENT OF STEEL Filed March 21. 1923 2 Shumta-Sheet 1 Nov.. 25, WM 1,517& 72

A. E. RUDD MUFFLE FURNACE FOR HEAT TREATMENT OF STEEL Filed March 21. 1923 2 Shets-5heet 2 Patents Nov. 25, 1924..

MUFFLE FURNACE FOR HEAT TEEATMENT OF STEEL.

Application filed March 21, 1923.

To aZZ whom it may concem:

Be it known that I, ALBERT EDWARD RUDD, subject of the King of Great Britain, residing at 20 Manlove Street, Wolverhampton, England, have invented certain new and useful Improvements in Muffle Furnaces for Heat Treatment of Steel, of which the following is a specification.

The invention relates to a furna ce having an enclosed main heating chamber suitable for heating `high speed ste-el and provides the hereinafter described and claimed improvements therein.

According to the invention a distnctive 1 Construction of furnace ofthe above type is provided comprsing a cylindrical man heating chamber adapted to be closed at both ends by doors or closing blocks and surrounded for the greater part of its length by a cylndrical flue the interior walls of which are parallel and into which the heating products enter tangentially at a position low down beneath the exterior walls of the chamber in such a manner that said prod-v ucts have a Whirling action imparted to them without any substantial longitudinal traverse of same taking place. Said products approximately describe a path underneath the chamber aforesaid to and over the top proceeding downwardly for a distance and then pass upwardly through a tangentally disposed exit flue arranged in the top wall of the cylindrical fiue where they enter a space constituting an upper heating chanber and are finally led away by a chimney for further utilization or dispersion.

By the above described Whirling action of the heating products there s a tendency to maintain same for a longer period of time 4:0 in close circulation with the outer walls of the main heating chamber, said products circulating at least once completely around the fiue enclosing the cylindrical tubular structure aforesaid. The gases or heating products do not enter the interier of the cylindrical chamber, but by the circulating motion around same produce theren a uniform heat.

Said doors or closing blocks are removable for repair-s and the like and also for permitting a rod or bar to be passed right Serial No. 626585.

through the interior of the main heating chamber should it be desrable to heat a portion intermediate of its ends although occasion rarely occurs. The cylindrical tubular structure may Conveniently be formed of carborundum, as also may be the doors or closing blocks and the main cylindrical flue,-the chief elements being enclosed and built up in suitable brick-work and encased externally and held rigidly by metal plates.,

A furnace according to the invention may or may not include a pre-heating chamber, but in either case a main top exit fine is provided, and if a pre-heating chamber is used a side door to open or close same is fitted, in which latter case the upper wall of the cylindrical fiue constitutes the bottom part of the pre-heating chamber.

The invention will be particularly described With reference to the accompanying drawings, wherein- Fg. 1 is a vertical sectional elevaton of a furnace according to the invention and Fig.

2 is a side sectional elevation of same. 7

The furnace is a rigid rectangular structure comprising side walls a, bottom a top a and front and rear walls a 66 encased by strong steel nlates c bolted to strengthening members d provided along the edges of the walls aforesad.

A main chamber e of cylindrical tube-like formation is disposed centrally and horizontally within a cylindrical flue f, said chamber e being supported laterally at or near its ends by the front and rear vertical walls of the structure enclosing the oylindrical flue f as shown in Fig. 2. Said structure is conveniently built up of six segmente f f f f f and 7" as shown, the external walls of 9 the segments 7", f f and f being substantially ciroular while the other segments f and f constitute the front and rear walls of said structure. The whole structure aforesaid is suitably supported by carborundum or other brickwork at the front, back, sides and bottom thereof as at g, 9 9 and g The cylindrical chamber e, aforesaid, is accessible from the :front and rear walls a a the 'ormer, more frequently used, being` provided with a sliding door 6 housed in guiding ways 6 6 rigidly carried by the front a while the back of the cylindrical chamber has a door or closing block 6 rigidly Secured by a det-achable plate e so that if it is desirable to heat a rod or bar intermediate of its ends the removal of theblockatoresaid allows the use of the'whole length of said lcylindrical chamber e from end to end.

The heating. products from their. usual source of supply enter the cylindricalfiue f by the pipe h disposed-low; down in: the furnace on one of the sides w and Conveniently embedded therein by carberundumaas at` h? and With fire clay 72?. Said products have a tangentia l fiew in relationte the flue f so thata whirli-ngaction is produced therei n and there is a te'ndency for said produetsto remain for alongperied oftime' incontaet with the outer p walls of said chambere, and to' crculate thereabou-t at least once completely round, it being particularly emphasized that the heating` products do not come into contaet with the work being heated ing ch'amber 7' is an exit' c'provid'ed With a in* theman ch'amber e'entry being prevented thereinto by j the closely tting walls' of the structure of the fiu'e f asth-is hasbeen found to be'undesirable. For adistance' down the periphe'ryon: one side of the cylindrical fi-'ue is provided an aperture j const-itut ing a mam flue exit which proceeds upW-ardly into a pre he'ating chamber j having anentrancej closed by a sliding deorj 'retained in guide ways: 7 3 j carred by the front w-all ofthe urnace'. The upper Wall j otsaid'cylindrical flue constituted bythe segments f f forms` the bottom or resting surface of the pre-heating chamber j where it is usual' in this type of furnace to heat toolsor the like in a moderate heatbefore subjecting same to the intense heat of the furnace proper.

Proceeding upwardl-y from the pre-heatdamper 76 from which' the heating` products areled away for further use orfor dispersion, but in` certain cases it may be desirable to build a furnace embodying the essential features of the nvention Without including the pre-heating chamber, so that the heating products after circulation in the main fluef a re-immediately led through an exit for the purpose aforesaid.-

It is desirable. to provide alighting or p 'safety hole into the main cylndrical fiue as at Zdisposed at right-angles to thetangenstial flowbf the heating products thereinto, said safety hole Z being suita'bly closed when the fu-rnace is in proper use. e

From the foregoing description it Will be apparent that the main cylindriea l chamber will be easily, renewable as may be desirable without breakingup or interier-ing with the main structure of-the furnace.

Opposite the entrance j t o the pre heating chamber j, a door or closing` bloekgmay be provided for 'e movalwhen pre-heating a bar or rod, same being detachably applied, tor example, as the removable block e.

Having now described my invention What l claim and desire to secure by Letters Patent iszc L In a 'furnace of the kind and for the purpose described the combination of a main cylindrical chamber, means for closing said chamber at both ends, a cylindrical flue surroundingsaid chamber for the grcater part of its length and whose interior walls are parallel; astangential inlet for the heating products into the cylindrical flue arranged low down beneath-x the exterior wa-lls of the chamber sot that said products have' awhirling motion inpartedsto them an exitupassing;` upwardly througlr the. top Wall of the eylindrical fine: at the side thereof; substantially as described.`

2. In a; furnace of the kind and fon' the purpose described the combination of a main cylindrical.chanber means :for closing` said chamber at both ends; a; cyliidrical flue` surrounding. said 'chamber for the greater part of its. lengthtandwhose interior Walls are parallel, a tangential inlet forth'e. heating products into' the cylindrical flue arranged low* down. beneath the: exterior walls of the chamber se; that said pro ducts have: a Whirling metion ,inparted to, them, a pre-heating chamber arranged above the cylindrical flue froni Where the heating products are. led away tor dispersion or further use.

3; In a turnace of the kind and for the purpose described thecombination of a main cylindrical ,chamber means for closing said chamber atbetlr ende, a cylindrical flue surrounding. saidcha-mber for the greater part of its length and whose interior walls are parallelg: a tangential entry for the heating products underneath ,the main flue se that the products proceed u nderneath the main heating. chamber to: the back, over the top and then downwa rdly for a distance, finally passing away upwardly through theexit flue to the pre-heating chamber.

4-. In: a furnace of the kind and for the purpose described theeombination of a main cylindrical chamber. means for closing said cha-mberat both ends, a cylindrical fiue surrounding said chamber for the greate part oli its length and whose interior Walls are parallel, a ta ngential inlet tor the heating products into the cylindrical fine arrunged low down beneath the exterior Walls of the chamberso that said products have a whirling motion imparted to them, removable doors or closing blocks provided' on each end of the main heating: chamber in. order to allow a clear all-through:.passage for. heating a bar or rod intermediate of its ends a .u d :tor `:faciltating repa'irs.

5. In a furnace of the kind and\ for the purpose described theconbinaton of a main eylndreal chamber, means for elosng said ehamher, a lighting 01' safety hole for startchamber at both ends, a cylindreal flue suring combuston and supplyng air disposed roundng said chamber for the greater part at rght-angles to the tangental flow of the 10 of its length and whose nterior walls are heating products into the cylindrcal flue. Parallel, a tangental nlet for the heating In testimnny Whereof I have hereunto set products into the cylndrcal fiue arranged my hand.

low down beneath the exteror walls of the ALBERT EDWARD RUDD. 

